This is another non-accounting voucher. However, it differs from the Memo voucher in that it is not a separate voucher type. You mark an existing voucher, (e.g., a payment voucher or a receipt voucher) as ‘Optional’. Press [CTRL]+[L] or click on the button. This button toggles with ‘Regular’. By marking it ‘Optional’ the voucher does not get posted anywhere but remains in the have the Optional Register.
To enable optional vouchers set Use reversing journals and optional vouchers? to Yes under F11: Features > F1: Accounts
You can make a voucher type default to ‘Optional’. This is done during creation of a new voucher type or alteration of an existing voucher type. (Gateway of Tally.ERP > Accounts Info > Voucher Types).
To mark a voucher type as Optional
Go to Gateway of Tally > Accounts Info. > Voucher Types > Alter.
Select a voucher type.
Set Make Optional as default to Yes.
Press Ctrl+A to accept.
After enabling this option, any vouchers entered using this particular voucher type will be marked optional.
Use of Optional Vouchers
Use Scenarios to see the effect of Optional vouchers entries on reports and statements
If a transaction has not been completed, you may not want it to affect the accounts. But you want to record it so that you simply modify the voucher and remove the ‘Optional’ mark by ‘Regularising’ it. Display the voucher in ‘Alter’ form and click on ‘Regular’. This way you can customize the voucher and then post it. E.g. Proforma sales invoice. In fact, an optional sales invoice prints as a Proforma Invoice.
You might want to see the impact of transactions without actually posting them. Optional vouchers allow you to do so. This not unlike the reversing journal.